The present invention relates to cigarette packing machines and more particularly has for its object an improved apparatus for the formation of regular groups or blocks of cigarettes to be packed.
There are known apparatuses in which a regular block of cigarettes, consisting for example of three superposed rows of respectively seven, six and seven cigarettes, is formed by separately preparing, at different row-forming stations, the rows of cigarettes, and by transferring simultaneously the single cigarette rows into receiving containers, subsequently arranged on a suitable endless conveyor, such as for example a chain conveyor or a rotary drum, which is moved with stepwise movement.
A known apparatus of the above described type is illustrated, for example, in the U.S. Arelt Pat. No. 2,334,142, precisely for the formation of a cigarette block composed of twenty cigarettes, arranged in three superposed rows of seven, six and seven cigarettes.
The feed hopper comprises twenty passageways divided into groups of seven, six and seven passageways, for feeding the single cigarettes, by gravity, to three separate row-forming stations, which are practically defined each by the abutment plate at the bottom end of the passageways. A stepwise-rotary drum is arranged for rotation before the row-forming stations, so as to bring a series of receiving pockets mounted thereon and provided with partitions for the cigarette rows, in axial alignment with the row-forming stations. During a dwell phase of the rotary drum, the receiving pocket aligned with the middle row-forming station receives the six-cigarettes row, while the receiving pockets at the right and at the left receive the bottom and top rows formed each of seven cigarettes, so that upon rotation of the drum, there is finally formed, in each pocket, a block of cigarettes of three superposed rows of seven, six and seven cigarettes, as desired.
The known apparatus of the above type presents some inconveniences, particularly when it is desired to employ it in association with high speed packing machines.
Firstly, there is required a tapered conduit or tubing acting as intermediary for the transfer of the cigarette row from the row-forming station into the receiving pocket of the receiving drum, said tapered conduit or tube being necessary to move laterally the cigarettes of a row so to bring them close to each other: in fact, when the cigarettes reach the row-forming station, there is a certain amount of side clearance between each of them, due to the total thickness (although kept to a minimum) of the partition walls forming the passageways from the hopper to the row-forming station. The use of the mentioned tapered conduit or tube, interposed between the row-forming station and the receiving pocket, requires a longer stroke of the ejector plates or pushers which effect the transfer of the row of cigarettes from the station to the receiving pocket.
Another limitation of the known type apparatuses resides in the fact that some of the passageways for the feeding of the cigarettes from the hopper to the row present a substantial inclination with respect to the vertical, which inclination slows down the descent by gravity of the cigarettes along the said passageways, and consequently the overall speed of the apparatus.
According to the invention, the apparatus for the formation of blocks of cigarettes does not effect directly the transfer of the cigarette rows from the row-forming stations into the receiving pockets of the receiving drum, said transfer being instead effected with the interposition of intermediate transfer drums, in the number of one for each row-forming station, each transfer drum being provided with a series of transfer pockets arranged angularly equispaced on the periphery of the drum, said transfer pockets coming successively into alignment with the row-forming station for receiving a row of cigarettes and in alignment with the receiving pockets on the receiving drum, for transferring the said row into the appropriate pocket. In this manner, the stroke of the ejector plate or pusher which transfers the row of cigarettes from the row-forming station to the transfer pocket of the intermediate transfer drum, and the stroke of the ejector plate or pusher which transfers the row of cigarettes from the transfer pocket into the receiving pocket of the receiving drum, are sensibly reduced with respect to the stroke which would be required by the ejector plate of the known type apparatuses, which transfers directly the cigarettes from the row-forming station to the receiving pocket, by passing also through the tapered conduit or tube.
According to another characteristic feature of the invention, which is rendered possible by the presence of the intermediate transfer drums, the row-forming stations are arranged in a horizontal plane. In this manner, the partition walls defining the passageways for the cigarettes from the hopper to the said row-forming forming station can be made vertical or slightly inclined with respect to the vertical, and can terminate at a certain distance from the cigarette abutment plate of the row-forming station, without any possibility of rolling of the cigarettes, and the said cigarettes can be brought together in close side-to-side relationship by any suitable means such as joggers of known type.